C. difficile leads to mild diarrhea to pseudomembranous colitis according to toxins. C. difficile associated 10-20% of all antibiotic-associated diarrhea forms and can be seen until after eight weeks of treatment with antibiotics. Antibiotics disrupt the integrity of the normal colonic mucosa, affect carbohydrate metabolism as a result of antimicrobial activity in the colon leads to the development of osmotic diarrhea and pathogenic bacteria associated diarrhea. The slowing of the metabolism of carbohydrates results in the reduction of short-chain fatty acids in the intestinal lumen and cause accumulation of carbohydrates which can not be absorbed. Besides the harm normal microbiota have provided the protective barrier and intestinal system becomes sensitive to resistant microorganisms. Reduction of intestinal lumen and in the number of Bacteroides and Bifidobacteria strains of facultative anaerobes (Fusobacterium the Clostridia, Eubacteria) results in the increase. Antibiotic-associated diarrhea, alongside a negative effect on the quality of life of the host, the cost of treatment in patients hospitalized in the hospital and also negatively affects the length of stay.